Apparatus for and method of smoothing pump bores



M. CASERTA Dec. 3, 1946.

APPARATUS FOR AND METHOD OF SMOOTHING PUMP BORES Filed April 17, 1944' 3Sheets-Sheet l 7 ||v|r.. 02 9 3 4 b 0O 7 4 7/ a 1] a w 9 a 7%6 b 2 "-wwwR 1 0 u v Michele Casefla Dec. 3,1946. M. CASERTA 2,411,851

APPARATUS FOR AND METHOD OF SMOOTHING PUMP BORES Fil ed April 17, 1944 Ys Sheets-She et 2 I Michele Caserla- Dec. 3, 1946. M. CASERTA 2,411,851

v APPARATUS FOR AND METHOD OF SMOOTHING PUMP BORES v Filed April 17,1944 3 Sheets-Sheet 3 M wks I Michele Caseria Patented Dec. 3, i946 sPATENT OFF-ICE APPARATUS FOR AND METHOD OF SMOOTHING PUDIP BORES MicheleCaserta, Detroit, Mich., assignor to Thompson Products, Inc., acorporation of Ohio Application April 17, 1944, Serial No. 531,430

' 14 Claims.

-This invention relates to an apparatus for and toa method of smoothingpump and other bores without substantially altering the generated boreshape or contour.

In the construction of rotary vane pumps such as described and claimedin my co-pending application Serial No. 397,763, filed June 12, 1941,the pump bore is so contoured as to make the operationof thepumpsubstantially non-pulsatring.v This is accomplished by forming the borewith a normal cross-sectional contour that comprises a pair of oppositecircle arcs having different radii but a common axis of generation, apairof opposite Archimedes spirals intermediate the circle arcs, andfour parabolic spirals joining the ends of the circle arcs to the endsof the Archimedes spirals, all of the curves having a common axis ofgeneration and common tangents at their points of juncture. A bore'ofsuch a contour is rather diflicult to form and to smooth properly, sincethe tolerances must, be held very close indeed and owing to thenon-cylindrical naturerof the bore, special tools andgrinding deviceshave to be employed.

. Iniaccordance with my present invention, the

boreyof a pump, or Ofa pump liner, is formed in a series ofoperations... In the case of a pump linen-a solid round billet is firstbored to form a cylindrical bore usingsubstantially the maximum lengthofradius that can be employed and yet have the cylinder lie wholly withinthe desired contour of the finished .bore. Ports are next cut in thesidewall of the liner and the proper contour of the bore 'formedthereinby cam turning or grinding, orby breaching. In this opera tion, the boreis formed accurately to. the desired contour, but, to a thousandth ofaninch or so under the final dimensions, just sufficient to permitthedesired amount, of smoothing in the subsequent honing operation.

In the smoothing operation, to which the pres ;ent invention moreparticularly relates, the

sive material carried externally by a pair of radially extensible bladesmounted in an adjustable assembly within a diametral slot in the end ofl a, rotatable spindle. The assembly includes means 5 provided by stripsof honing stones or other abrafor forcing said blades radially outwardlyand for operating said means to adjust the position of said blades untilthey span a diametral length equal to the diameter of the finished bore.The smoothing operation is efiected by rotating and reciprocatingthe-spindle carrying the blade relative to the pump liner. In asmoothing operationas carried out by a, device of my invention, theradially extensible blades oscillate as a unit in the diametral slot ofthe spindle end to follow the contour of the bore as initially formed inmuch the same way as do the slidable vanes of the rotor in the finishedbore of a pump liner during the operation of the pump. Accordingly, itis possible by the use of my invention to smooth a generated pump borehaving a constant. diametral dimension through its axis of generation ina very simple and efficient manner, while holding the bore to very closetolerances.

It is therefore an important object of this invention to provide anapparatus for smoothing bores of pumps, pump liners or the like wheresuch bores are of a generated contour having a constant diametraldimension through a common axis of generation. I

It is a further important object of this invention to provide a simpleand rapid method of smoothing the internal surfaces of pumps, or pumpliner bores, and the like where such surfaces are formed from aplurality of curved surfaces having a common axis of generation andcommon tangents at their lines of juncture, but are not cylindrical.

Other and further important objects of this inventionwill be apparentfrom the disclosures in-the specification and the accompanying drawingSiOn the drawings:

Figure l is a side elevational view of an apparatus embodying myinvention;

'Figure 2 is a fragmentary, front elevational view to illustrate theoperation of the clamping mechanism for holding said pump liner in position'during the honing operation;

- Figure 3 is a fragmentary, top plan View of the view of thepumpliner'of Figure 5 indicating the axis of generation and the radii of thearcs and curves of which the pump bore is composed;

Figure 7 is a partly diagrammatic view of a point of its reciprocatingmovement and with the honing strips radially retracted prior to thestart of the smoothing operation, with parts in elevation;

Figure 9 is a view similar to Figure 8 but with the honing device at thetop of its strip and with the honing strips in operative position, withparts in elevation;

Figure 10 is a top plan view of the honing device;

Figure 11 is a sectional view taken substantially along the line XI-XIof Figure 9; 1

Figure 12 is a sectional view taken substantially along the line XIIXIIof Figure 8 with parts in elevation; and

Figure 13 is a sectional view taken substantially along the lineXIII-XIII of Figure 9.

The reference numeral Ill (Figure 1) indicates generally a platform orbase from which is mounted an upstanding post H for supporting thehoning apparatus of my invention. Said apparatus includes a work tableI2 adjustably mounted upon said post i! and adapted to be held inadjustedposition thereon by means of a thumb screw 1%.

The work table 12 is provided on its upper face with an annular,recessed holder 53 for receiving the lower end of a pump liner I l. Saidholder 13 may be integral with the work table [2 or fixedly attachedthereto byany suitable means. The holder i3 is provided with acylindrical socket I 5 for receiving the lower edgeof said pump liner Itwith a snug fit. Both the table 12 and'holder 13 are apertured, asindicated by the dotted line I6, to permit the honing device to projectupwardly therethrough into the interior of the pump liner l4.

Also supported upon the table 12 is a clamping mechanism, indicatedgenerally by the reference numeral 11. Said clamping mechanism I!(Figure 2) comprises a pair of upstanding plates i8 secured to said worktable '5 2 in any suitable manner and having a spacer block 59positioned therebetween. A rearwardly and upwardly inclined arm 26 isrigidly held at its lower end between said spaced plates H] by means ofpins 2| and 22 extending therethrough. At the upper free end of said arm28 there is pivotally mounted to said arm, by means of a pivot pin 23, apair of lever arms 21 having bowed-apart end portions 24 and 25. A strip28 extends between said end portions 25 and 25 inwardly of theirextremities. A lever arm 29, having at its upper free end a handle 28,is pivotally mounted at its lower end, as by means of a pivot pin 3!,between said upstanding plat-es i8. Said arm 29 is also pivotallyconnected near its free end, as at 33;, to a pair of short links 33. Theother'ends of said links 30 are pivotally connected as at 32 to the arms21. The outer free ends 23 and 25 of the lever arms 21 carry members 34and 35, respectively, that are provided with dependent clamping portions35 and 31, respectively, adapted to overlie and engage the upper edge ofa pump liner l4. Said cross strip 26 is provided with a down-- wardlyextending pin 38 for reception in a recess or socket 359. There is onesuch pin receiving recess or socket 39 in each end of a pump liner l4(Figure 5).

As shown in Figure 2, when the clamping and holding mechanism is in itsoperative position, the pin 38 extends into the pin receiving socket 39and the pump liner engaging portions 36 and 31 are clamped over theupper edge of a pump liner I4. In this position the lever 21 issubstantially horizontal and the lever 29 lies forward of the'axis ofthe pivot pin132, which may be considered to bathe dead center point ofthe mechanism. Accordingly, in its normal position,

the clamping mechanism can be thrown out of clamping engagement only bya manual pull upon the handle 28 to draw the lever arm 29 back and thuslift the arm 21. The clamping mechanism,

' in its inoperative position, is illustrated in dotted lines in Figure2.

There is also mounted for adjustment upon the post ll (Figure 1) adriving mechanism, indicated generally by the reference numeral 40,which comprises an arm 4| provided with a bore 42 through which saidpost I I extends. A thumb screw 43 is provided for locking the arm 61 inadjusted position upon said post. A motor 44 is attached to said arm 4!at one side of the post H. Said motor has a vertical drive shaft nearthe lower end of which is mounted a pulley 46. Said pulley 46 is adaptedto drive, by means of a belt 11, a secondpulleyJlB mounted upon thelower end ofya spindle 49 that extends through a bore 50 in the free endof said arm 4|. A second pulley 5| is mounted upon the extreme lower endof said motor shaft and is adapted to drive a disk 52 mounted upon a pin53 from the side of the motor housing. Since the pulley 5| and disk 52are in planes at right, angles to each other, a pair of small pulleys 54and-55 are used to guide the driving belt 55 that extends around saidpulley 5i and disk 52. Said small pulleys 54 and 55 are supported fromthe motorv housing by means of a branched supporting bracket 51.

The pulley B8 is mounted upon the lower end of the spindle 49 so thatsaid spindle 49'm'ay be rotatedby the motor 44 acting through the drivepulley 46 and the drive belt 41. The hub 58 of said pulley 43 is keyedon said spindle 49 by means of a spline 59 so as to permit reciprocalmovement of said spindle. 49 along its vertical axis, while the hub 58is held against displacement vertically between the horizontal arms of aU-shaped bracket fixedly secured to said arm ll. The horizontal arms ofthe bracket Bil are apertured, as at 6|, to permit free passage of thespindle 49 therethrough.

A sleeve 62 is mounted upon said spindle 49 nea its upper end between'apair of fixed collars 63 and 64; Said sleeve 62 is loose upon thespindle Mi but because-"it'is held between the collars 63 and 64 iscapable of transmitting axial movement to said spindle t9. .Such axialmovement is accomplished through a crank arm 65, one end 66 of which isadjustable in a slot 51 of said disk The other end of said crank arm'65is connected by means of a pivot pin 68 to one end of a rod 55. Theother end of said rod 69 is provided with an eye 10 which engages ashaft 1| journaled in the spaced dependent sidewalls 12 ofsaid table i2.A pinion 13 is fixedly mounted upon said rotatable shaft 1|, so that asthe disk 52 is revolved, the crank arm 65,-acting through the rod 53,causes said pinion 13 to revolve first in one and then in the otherdirection Said pinion13 meshes with a rack 14 formed in the sleeve 62,whereby said sleeve 52, and consequently the spindle 49, is caused toreciprocate vertically 'whenthe motor is running...

upper end of the spindle 49sis.providedwith adiametr'alIslotl5-whichextends clear to the end of said spindle and ispartially .closed by anoverlying'clisk .I6he1dthereon by means of screws'I'Iu (Figure 10) Within said slot I is mounted the smoothing .or honingmechanism, .indicated generally by the reference numeral 11., Saidmechanism 1'! comprises'a pa'ir'of members. "I8 and I9, heldagainst'axial displacement between the bottom 86 of said slot I5 and theunderside of thecover disk I6 but-bodily movable laterally within saidslot I5. Each of said members I8 and '19 is longitudinallygrooved forreceiving abrasive strips 8| and 82; respectively. Said strips! and 82may suitably comprise honing stones and are replaceable when 'worntoothin.

The members I8 and 19 are provided'along their inner edges withopposed'tapered extensions 83 and 84 (Figure 11) that serv'e' to givesaid members wider areas of contact with the walls ofthe slot I5 andthus prevent said members from wab-bling or becoming cocked in saidslot. Each of said members I8 and I9 is further provided atlongitudinally spaced points along their lengths with inwardly directedabutment portions' 85 and 85a, and 86 and 86a for a purpose thatwilllater appear; Said members lsan'd I9 are also provided with transverseslots 8'! and 81a (Figures 8 and 9) for a purpose that willpresently bedescribed. I

- Meansare provided for forcing said members I8 and'I9 laterally apartwithin the slot I5. Such means include an integrally formed member 88(Figure 12) provided witha "slot lfl9 extending laterally completelytherethrough. "Said :member 88 (Figure 8) is formedwith' a wedge-shapedportion 89 at its upper end, liiav'ingupwardly' convergent outer faces96 and90a, andat its lower end with awedge-shape'd' portion 9!havin'gialso upwardly convergent edges 92 and 92a.-' A rod 93 isprovided with a lower threaded portion 94 that is adapted to be engagedin a threaded bore provided forthat purpose in'the upper end of saidz'ri embertlig- Said rod 93 carries at its upper free end a'knur'ledhead 95 to facilitate its manual operation. At itslower end the rod 93is provided with a portion 96 of reduced diam: eter which is freelyreceived in a soclset formed in'a floating bridge member 9'I.' Saidbridge member 91 extends through the slot'-I89 in said member 88 andtheends of said bridge'member extend freely into the slots 91' and 81ainsaid members wand- 19.- a I 1 With the'honing mechanism 11 in theposition shown in Figure 8, that is with-the members I8 and I9 in'their'inwardly retracted state, a pump liner I4 can be slipped over theupperend of said mechanism and clamped in place upon the work table I2. Thethreaded shaft 93 is then manually turned to move'the honing stripcarrying: members I8 and I9 outwardly into the position illustrated inFigure 9. Upon threading said shaft 93'intothe r'nember 88, said member88 is drawn upwardlyand theaction of the 'tapered surfaces 85 and 85:1,;and 86 and 86a,

working uponthe corresponding abutments 85 and 85a and 86 and 86acausesaid'members I8 and I9 to be spread apart laterally until thesurfaces of the honing strips BI and 82 are in working engagement withtheinside surface of the pump liner lfll The bridge 91, into whichthellower end ofthe shaft 93 extends, prevents longitudinal movement ofsaid shaft 93 when it is being threaded 1 into or out of; the member 88and'thus causes relative 'a'xialmovement ofthe other, throughout their'length while being moved radially outwardly during manual operation ofthe rod-93.5.-.

In =1 )reparing..:appumplinerI4 for the honin operationabout to bedescribed, a solid cylindrical billet may first be provided with aneccentric but truly cylindrical bore. I60 (Figure 7) by means ofa;reamer IOI. Said bore I 00 is then re-formed to'the desired contour ofthe finished pump 'linergasior. instance to the contour indicatedby thedotted line I02. This may be accomplis'hed by broaching. Ports I03 andI04 are cut into the: wall of the pump liner to the size and shapedesired, either beforeor after the breaching operations The pump linerI4 is also provided, prior to the honing operation, with the pinreceiving recesses 39 (Figure 5) extending inwardly from each of thesendfaces on thethicker side ofthe 'pump liner. These recesses 39 also servean' alinement' purpose in the assembly of the pump-liner in a pump suchas. shown in my 00-- pending application Serial No. 397,7 63, filed June12,1941 I v v:"The bo'rei I92 .atthe start of the honing operation isslightly .undersize' as'compared with the final dimensions of the boreIDZa (Figure 6)'in the finished pump liner. "Thecontourof the bore will,in accordance with known principles, have a common axis of generation,indicated bythe let'- ter A (Figure 6'): which will be concentric withrespect to the outer cylindrical surface I05 of said pump'liner. -All'of the diameters of the pump bore1'I82a passingvthrough said common axisof generation A will, of course, be of equal length. In accordancewithone method of obtaining a non-pulsating pump, the contour ofthe bore I02a isformed by a pair of opposite circle arcspdefined at'theirextremitiesby thepoints -I 06 and H11, and bythepoints I88 and,,I09,formed with unequal radiiz-R and r,-respectiv ely, Intermediate theextremities' ofsaid arcs I06--I 81' :and- I08-I 09 are a pair ofArchimedes: spirals Lille-III and H2- H3, which are joined to theextremities ofthe circle arcs, by four parabolic spirals, [OB-H2,IUI-IIO,il08- -III, and I09-II3. All of these arcs and 'curveshave, acommon axis of generationsA, and they also ,have common tangents attheir. points; of junction. All of the diameters passing'through saidcommon axisiof generation A, such asthe diameters I66-.A -Iil8and I0fI-ing of'non eylindrical bores, which are nevertheless formed withiacommon axis of. generation and'with diameters of constant length.

The operationnot my honing device will now be described:

A pump liner-I4 is inserted over the upper end of the spindle 49carrying the honing device with thehoning strips 8i and 82 in retractedposition, as'illustrat'edin Figure-8; The pump liner I4 fitssnuglyin-totheirecess I5 of the holder I3; The

clamping- J mechanism 1 I1 i :then moved into clampingposition-, asillustrated in full lines in 7 Figure 2, the liner [4 having previouslybeen turned until the centering and aligning pin 38 can be inserted intothe socket or recess 39. The lever 29 is then thrown over beyond thedead center to clamp the pump liner l4 securely in the holder l3.

Next, the rod 93 is manually turned to draw upwardly the blade spreadingmechanism 11 and thus force the honing strips 8| and82 outwardly intofirm working engagement with the interior surface of the bore |02a.

The motor 44 is next started up to begin the honing operation. Duringthe operation a cooling fluid, such as kerosene, may be run over theentire honing mechanism. The skirt |2| protects the driving mechanismfrom the kerosene. The length of the reciprocating stroke of the spindle49 should previously have been adjusted, by adjustment of the eccentricpin 66 in the slot 61, so that at the extreme positions of the spindlein its stroke, the honing strips 8| and 82 always span the full lengthof the pump liner |4, that is, at the lowermost position of the spindle,the upper ends of the honing strips 8| and 82 (Figure 8) do not passbelow the upper end of the pump liner l4, while at the extreme uppermostpoint of travel of the spindle 49, the lower ends of said honing strips8| and 82 still lie below the bottom edge of the pump liner M. Thisprovision is importantif a straight Walled bore, rather than a bellmouth bore, is to be obtained. The amount of the reciprocation of thehoning strips 8| and 82 is preferably such as not to bring the ends ofsaid strips within the cut-out wall portions forming the ports I03 andI04, since there would then be a tendency for the ends of the strips, ifcoming within said cut-out portions, to catch on the.

edges of th port openings and eitherbe damaged or wear away said edgesunevenly,

In usual practice, the amount of abrasion of the wall of said bore I02effected by the'honing operation is of the order of 0.001 inch and isnot intended to accomplish other than a, sufficient smoothing operationto make possible a smooth sliding fit between the bore and the vanes ofthe rotor when the pump is assembled in an operating condition.

As the spindle reciprocates, it is also rotated by the drive includingthe pulleys 46 and 48 and the driving belt 41. in the neighborhood of400 R; P. M., but slower or faster rates of revolution can be employeddepending upon the type of work being done. As the spindle rotates, theentire blade carrying mechanism H oscillates as a unitlaterally in aseries of diametral planes, the honing strips 8| and 82 remaining infixed spaced relationship relative to each other. The movement of theassembly is similar to that of .the vanes of a rotor in the operation ofa vane type pump. During such displacement along their diameters, themembers 18 and 79 slide Within the slot with their upper edges confinedby the closure J6. and with their lower edges resting against the lower.wall 80 of said slot 15. As previously explained,

the extended contact surface areas provided by the extensions 83 and 84between said members 18 and I9 and the lateral walls of said slot 15 Ytend to prevent wabbling or cocking of the members within the slot.

During the honing operation, it maybe desirable to adjust the honingstrips 8| and .82 outwardly into closer pressure relationship with thesurface of the bore undergoing the smoothing operation. This can beaccomplished without stop- The rate of rotation is suitably ping themotor 44 by merely grasping the knurled end 95 and giving the rod 93 atwist. With a fair amount of experience, an operator can easilydetermine to what extent to adjust the diametral span of the abrasivestrips 8| and 82, and adjustments are made whenever necessary during theoperation of the device without interrupting rotation ofthe spindle.Ordinarily, the honing operation requires avery brief period.

The necessity for the smoothing operation arises from the fact that thebore cannot be perfectly formed in the first instance by broaching orthe like. Also, there is usually some distortion due to the heattreatment step that follows broaching.

It is important to note that the method herein described does notcontrol the shape of the bore other than to insure constant diametrallength, but is effectiveonly in giving to the bore a smooth finishwithout substantially altering the generated bore shape, and in makingsure that all diameters through'the axis of generation A will haveexactly the same length. This insures that the pump vanes will haveexactly the same end clearance in all positions of the vanes within thebore.

If desired, the work table I2 can be swung very slightly one way or theother to cause the abrasive strips 8| and 82 to bear more heavily whenriding across the ports I03 and I04, thus giving more clearance at thosepoints and closer clearance in the pumping zones between ports, when theliner is assembled and the pump is in operation.

In order to permit the honing strips to be changed without taking theclosure disc 16 off and lifting the mechanism 1'! out of the slot 15,the rim of the annular holder l3 (Figure 3) is cut away at oppositesides as at I20, to the lower edge of the liner. The strips 8| and 82can thus be removed laterally and changed with a minimum of effort. v

It will, of course, be understood that various details of constructionmay be varied through a wide range without departing from the principlesof this invention and it is, therefore, not the purpose to limit thepatent granted hereon otherwise than necessitated by the scope of theappended claims.

What I claim is: I

1. Apparatus for honing the internal surface of a hollow article, thebore of which has been formed with joined dissimilar surfaces ofgeneration having a common axis of generation and diameters of constantlength, said apparatus comprising a rotatable and reciprocable memberhaving a diametrally extending slot, radially adjustable blades slidablypositioned for movement in said slot and having strips of honingmaterial projecting outwardly therefrom, means for adjusting said bladestobring said honing material into working contact with said internalsurface and hold said blades after adjustment in rigidly fixed spacedrelationship, and means for rotating and reciprocating said memberwithin said bore to effect the honing of said surface to smooth the samewithout materially altering the curvatures of said surfaces ofgeneration, said blades being freely oscillatable in said slot duringsaid honing operation to permit said honing material to follow thecontour of said internal surface.

2. Apparatus for honing the internal surface of a hollow article, thebore of which has been formed with joined dissimilar surfaces ofgeneration having a common axis of generation with all of the diametersof said bore, passing through said axis of constant length, saidapparatuscomwardly therefrom, means for adjusting said blades to bringsaid honing material into working-contact with said internal surfaceincluding means for holding said honing-material in adjustedextended'position'with the desired contact pressure against saidsurface, and means for rotating and reciprocating said member-withinsaid bore to effect the honing of said surface to smooth the same,said'blades and blade adjusting and holding means being freelyoscillatable in said slot to permit said honing material to follow thecontour of said internalsurface withoutmaterially altering thecurvatures of said surfaces of generation;

3. Apparatus for honing the internal surface of a hollow article, thebore of which has been formed with joined dissimilar surfaces ofgeneration having a common axis of generation and constant diametraldimensions, said apparatus comprising an adjustable supporting fixturefor holding said article with the bore thereof unobstructed, arotatableand reciprocable member having a diametrally extending slot, an assemblyslidably positioned in said slot and having strips of honing materialprojecting outwardly therefrom, means associated with said assembly forextending said blades to bring said honing material into working contactwith said internal surface, and means for rotating and reciprocatingsaid member within said bore to effect the honing of said surface tosmooth the same, said assembly being freely oscillatable in said slot topermit said honing material to follow the contour of said internalsurface without materially altering the curvatures of said surfaces ofgeneration.

4. In an apparatus of the class described, a member having a diametralsl'ot, radially opposed blades insa dslot carrying outwardly projectinghoning surfaces, tapered rigid elements between said blades and incontact therewith for moving said blades into radially extendedpositions, and an adjusting member cooperating with said taperedelements to effect such radial extens on of said blades and said taperedelements, said blades being oscillatable as a unit in said slot along adiametral plane without change in diametral length.

5. In an apparatus of the class described, a member having a diametralslot, radially opposed blades in said slot carrying outwardly projectinghoning surfaces, means associated with said blades for moving saidblades into radially extended positions and providing a rigid backingfor said blades, and an adjusting member cooperating with said means toeffect such radial extension of said blades, said blades and said rigidbacking means being oscillatable in said slot along a diametral planewithout change in diametral length.

6. In an apparatus of the classdescribed, a member having a diametralslot, radially opposed blades in said slot carrying outwardly projectinghoning surfaces, tapered elements between said blades for moving saidblades into radially extended positions and providing a rigid backingfor said blades, and a manually operable threaded adjusting membercooperating with said tapered elements to effect such radial extensionof said blades, said blades and tapered elements being oscillatable as aunit in said slot along a diametral plane without change in diametrallength.

'7. In an apparatus of the class described, a.

T cylindrical member having" 'a' slot extending diametrallytherethrough,a pair of radially opposed blades mounted in said slot formovement therein along a diametral plane, honing strips carried by saidblades and projecting outwardly therefrom, tapered elements for engaginginternal faces of said blades, adjusting meansassociated with saidtapered'elements for moving said blades radially outwardly uniformly oftheir lengths, said-adjusting means including an'ex- .tension'projecting beyond an end of said cylindrical' member and manuallyoperable during rotation of said cylindrical member, said honing strips,tapered'elements and adjusting means constituting a unit of rigidlyfixed diametral length for any given adjustment and said-unit beingmovable in said slot, and means forrota'ting said cylindrical member tocause said honing strips to smooth an internal bore with which saidstrips may be adjusted into contact.

8. In an apparatus of the class descr bed, a rotatable and reciprocableshaft having an open ended slot extending through the axis thereof, aclosure member for the end of said slot and an assembly retained by saidclosure member and freely oscillatable in said slot as a unit of fixeddiametral length during operation of said shaft including outwardlyprojecting parallel strips of abrasive material for the smoothing ofinternal surfaces.

9. In an apparatus of the class described, a rotatable and reciprocablemember having a slot extending through the axis thereof and an assemblyfreely oscillatable in said slot during operation of said memberincluding outwardly projecting strips of abrasive material for thesmoothing of internal surfaces, said assembly also including taperedelements associated with said strips for moving the same into outwardlyprojecting position and means for actuating said tapered elements duringoperation of said member.

10. In an apparatus of the class described, a

rotatable and reciprocable member having a slot eration of said memberincluding outwardly projecting strips of abrasive material for thesmoothing of internal surfaces, said assembly also including taperedelements associated with said strips for moving the same into outwardlyprojecting position and means for actuating said tapered elements duringoperation of said member, said means including a floating bridge and amanually operable member coacting therewith to cause said taperedelements to force said strips outwardly.

11. The method of smoothing an internal non- .cylindrical surfacecomposed of a plurality of dissimilar surfaces of generation having aconstantdiametral length through the common axis of generation of saidsurfaces, said method comprising adjusting a pair only of honingsurfaces radially outwardly into working contact with said internalsurface, said honing surfaces being maintained in parallelism in allpositions to the common axis of generation and being oscillated -withoutrelative movement therebetween in planes passing through saidcommon'axis of generation and rotating and reciprocating said honingsurfaces relative to said internal bore surface.

12. The method of smoothing an internal surface the contour of which iscomposed of a plurality of dissimilar surfaces all having a common axisof generation and the diameters of which passing through said commonaxis are all of con- 'stan-t length, said method comprising adjusting apair only of honing surfaces radially outwardly into pressurerelationship with said internal surface throughout the length thereof,holding said honing surfaces in relatively fixed spaced parallelrelationship to the common axis of generation but freely oscillatable inall diametral planes .passing through said common axis of generation androtating and reciprocating said honing surfaces relative to saidinternal surface While maintaining said honing surfaces at all timesparallel to each other and in abrading relationship to said internalsurface to smooth the same.

13. In an apparatus of the class described, a rotatable and reciprocableshaft having an axially elongated slot extending transverselytherethrough, and an assembly confined within the axial length of saidslot but freely oscillatable as a unit of fixed diametral length in saidslot trans- .versely of said shaftduring operation thereof,

said assembly including a pair of diametrally op- .posed, outwardlyprojecting, narrow strips of abrasive material for the smoothing ofinternal surfaces.

14. In an apparatus for finishing a generated bore the cross section ofwhich is characterized by the diameters through its center of generationbeing all of the same length, a member rotatable about the axis ofgeneration of said bore and axially reciprocal along said axis, saidmember being provided with a slot in a plane passing through said axis,and an assembly in said slot oscillatable therein as a'unit, saidassembly including a pair of opposed parallel abrasive strips to contactthe wall of said bore and including means to positively spread saidabrasive. strips While keeping the same parallel to said axis.

MICHELE CASERTA.

